Furnace damper



Aug. 13, 1935. 1 w FRANZ 2,011,103

FURNACE DAMPER Filed March 16, 1954 /Nvf/vroe.- JOHN hf. FPA/vz.

q TToR/VEK Patented Aug. 13, 1935 FURNACE DAMPER "VJohn W. Franz, St. Louis, Mo., assigner of onehalf to Lawrence J. Rasse, Fairbury, Nebr.

Application MarchV 16, 1934, seria; N0.71`5,sf19

1 Claim.

`My invention has relation to improvements in furnace dampers and it consists in the novelfeatures of construction more `fully set forth in the `specification and pointed out in the claim.

AThev invention is principallydirected to a combinationhdamp'er andcheck-valve'located in the smoke pipe or iiue leading to the re-box of the furnace, and it has` for its principal object the combining of the damper and check-valve ina single unit. that is inserted in the' smoke pipe. Another object of the invention isto arrange the damper and check-valve in cooperative relation so that on operatingV the check-valve the damper will be automatically opened or closed toa proportional degree with the closing or opening of the check. In other words, as the check-valve is opened the damper is closed, and as the checkvalveis closed the damperis opened.

IA further object of the invention is to provide a by-pass so that there will always be a passageway for the escape of gases, irrespective of the position of the damper, and means are associated with the damper for keeping the by-pass free from soot accumulations. Other advantages inherent in the invention will be better apparent from a detailed description thereof in connection with the accompanying drawing, in which:

Figure 1 is a side view of an ordinary hot-air furnace showing my invention applied to the smoke pipe thereof; Fig. 2 is an enlarged side elevation of a section of the smoke pipe showing my improved combined check-valve and damper applied to the smoke pipe; Fig. 3 is a vertical cross-sectiontaken on the line 3--3 of Fig. 2; Fig. 4 is a top plan of the combined check-valve and damper mounted in the smoke pipe, with parts, however, broken away to show other parts in section; Fig. 5 is a vertical longitudinal section taken on the line 5-5 of Fig. 3 with the checkvalve closed and damper open; and Fig. 6 is a. similar section of that shown in Fig. 5 except that the check-valve is open and the damper closed.

Referring to the drawing, F represents a conventional hot-air furnace equipped with the usual flue or smoke pipe P, to which isV applied my combined check-valve and damper A. The combined check-valve and damper may be termed a valve mechanism as the check-valve I and the damper 2 are mounted in the housing 3 so as to form a unitary structure capable of being applied to the smoke pipe P by merely cutting an opening ol of the proper size in the smoke pipe and securing the housing thereover. In the present instance, the housing is secured to the smoke pipe by a plurality of bolts 4 passed through each of the sidewalls 5 of the housing adjacent to their lower edges and the portion of the smoke pipe along the margin of the opening o (as shown in Figs. l and 5). The housing 3 forms a boxlike superstructure above the smoke pipe P havi desired. The check-valve I has sides or wings 8', 8 shaped according to sectors of a circle and is rotatably mounted on a hinge pin 9 located on the geometrical center of said sectors, said pin .passing through the walls 5, 5 of the housing and having its endsslightly upset to prevent its dislocation. l A ap valve I!! is rotatably mounted in the sides 5, 5 of housing 3 and the hinge pin II, to which `the flap valve is secured, passes through the sides 5, 5 of housing 3 on the center of the arc describing the arcuate rear portion 6" of the top surface 6 of said housing. The lower edge I of the flap valve I is semi-circular so as to t snugly in the smoke pipe P while the upper edge I0 is straight and is approximately in the plane of the top surface of the smoke pipe when the damper 2 is in its vertical or closed position. Secured to the damper II] (preferably by welding) is a rectangular frame I2 having the component I3, which forms its outer margin, ly-

Ving in close proximity to the inner surface of the arcuate portion 6" of the housing 3. The hinge pin II has its ends I4 extended at right angles to the pin proper to form arms which will engage with cam elements I5, I formed on the wing 8', 8 for a purpose presently to appear. It will also be observed that on one of the sides 5 of housing 3 is a spring catch I6 slightly below the plane of the arms I4 when the damper I0 is in its horizontal or open position. There are also a pair of spaded bosses I I having threaded openings I8 on one of the sides 5 for the purpose of receiving a stud I9 to limit the amount of closing movement of the damper IU. The positioning of the stud I9 in either of the bosses II constitutes a matter of permanent adjustment for the particular furnace to which my improved device may be applied.

The operation of the invention is as follows:

In order to give the furnace F its maximum draft the operator releases the chain C so as to permit the check-valve I to close by gravity. As the valve descends the cam elements I5 on the wings 8' bear downwardly on the arms I4 to raise the damper IU which assumes a horizontal position when the check-Valve is fully closed as shown in the drawing. It will be observed that as the damper i!) is swung upwardly the component i3 of the frame l2 moves along an arouate path in close proximity to the arcuate portion E" of the housing 3. During this, any soot accumulations on the inner surface of the housing 3 are wiped or scraped from the surface. Obviously, when the check valve l is raised for the purpose of checking the draft, the damper i0 moves downwardly to assume a vertical position when the check Valve is fully opened. During this movement of the damper the frame i2 is again rotated to remove soot accumulations. Thus every time the dampers are operated any accumulated soot will be removed from the arcuate portion of the housing 3. This prevents the building up of soot accumulations which, if allowed, would ultimately restrict the passage he tween the damper iii (when closed) and the portion 6 of the housing. It is one of the objects of the invention to constantly maintain this passage for a lay-passV so that ev-en when the dampers are in position to fully'check the draft through the smoke pipe P there will still he suicient draft to carry products of combustion out of the furnace and through the flue.

It is well known that the amount of draft will vary for different furnaceinstallations, depending on other factors, such as the character of the chimney, and in order to make suitable adjustment to compensate for such variations I have provided a stop pin or stud i9 which may be inserted in either of the threaded openings It to limit the closing movement of the damper il). When the stop pin is in place one of the arms i4 will impinge on it and be arrested in its upward movement when the gate-valve i is raised, and even though the gate-valve may be raised to its maximum position the damper l0 will not move further after the arm M engages the stop pin. consider this a desirable feature as in some furnace installations there may not be suicient draft to carry ofic the products of combustion if the damper lil is allowed to swing entirely to closed position.

The purpose of the spring catch IG is to serve as a detent for the damper so that it may be maintained in `open position irrespective of the position of the gate-valve if desired. It might be desirable to temporarily lock the damper in open position if the operator is removing ashes from the ash pit and the gate-valve is held in open position at some point removed from the furnace.

From the foregoing it is apparent that I have provided a combination check-valve and damper that is simple and certain in its operation, and

vdue to its compact unitary structure may be easily applied to any furnace without any alterations beyond those which are necessary for the mere insertion of an ordinary check-valve.

Having described my invention, I claim:

A device of the character described comprising a housing, a check-valve, a damper mounted in said housing, said check-Valve and damper being cooperatively associated so that upon the operation of one Ythe other will be automatically operated, and the damper having its upper end spaced from the wall of the housing containing the check-valve to provide ahy-pass adjacent to said check-valve when the damper is closed, and a scraper projecting from the damper to close proximity 'with the housing walls and movable so as to scrape the accumulations therefrom and maintain the space between the damper and said walls.

.JOHN W. FRANZ. 

